Trackball



FIG. 1 is a top plan view of a trackball showing our new design;

FIG. 2 is an end elevational view of one end;

FIG. 3 is an end elevational view of the other end;

FIG. 4 is a bottom plan view;

FIG. 5 is a side elevational view of one side; and

FIG. 6 is a side elevational view of the other side. 

The ornamental design for a trackball, as shown and described. 